风力发电机组升压变压器的雷电电涌防护

Lightning Surge Protection for Step-Up Transformer in Wind Turbines

风电的快速发展带来了包括雷电灾害等亟待处理的问题。为了合理保护风力发电机组升压变压器等集电设备,需要研究雷电电涌对其危害。利用ATP-EMTP软件搭建完整风电机组模型,分析不同雷电参数、不同接地电阻情况下变压器低压侧电涌过电压,最后计算低压侧避雷器失效概率。仿真结果表明:雷电流波头时间越短,强度越大,变压器低压侧电涌过电压越大;接地电阻对电涌过电压影响较大;接地电阻的增大增加了避雷器的失效概率。在升压变压器低压侧安装避雷器可以有效保护变压器,但是需要尽可能降低接地电阻值。

The rapid development of wind power generation has brought problems involving lightning disasters to the fore. In order to protect the step-up transformer in wind turbines properly, it is necessary to study the harm of lightning surge on them. A complete model of the wind turbine is established in ATP-EMTP. The surge overvoltage at the low voltage side of transformer under different lightning parameters and different earth resistances are analyzed. Finally, the failure probabilities of low voltage （LV） side arresters are calculated. The simulation results show that： the surge overvoltage on LV terminal of the step-up transformer increases with shorter front time and higher lightning current amplitude; the earth resistance also has greater effect on the surge overvoltage; the failure probabilities of the arresters increase with the rising of earth resistances. Installing surge arresters on the LV side will protect the step-up transformer effectively, but it is needed to reduce the earth resistance to as low as possible.